In the practice of medicine in hospitals, blood samples are routinely taken from patients by such personnel as medical technologists (hereinafter, "phlebotomists"), which blood samples are then analyzed to afford a variety of test results such as the concentration levels of various chemicals or other substances in the blood. The hypodermic syringes and bottles and like equipment used in blood sampling are commonly carried in a tray which is transported from patient to patient by the phlebotomist as the latter moves through a hospital. When preparing to draw blood from a patient, the phlebotomist places the equipment tray on a bed-side stand or an overhanging bed table, or on the bed itself, which surfaces, it will be understood, may often be highly contaminated with, for example, blood, phlegm, mucus, urine and feces from urinals and bed pans, scraps of food, spilled beverages, etc. The movement in this manner of the tray from patient to patient, it will be understood, may well serve to transmit diseases from patient to patient.
Modern hospitals are acutely aware of the problem of disease transmission from patient to patient, and well-run hospitals take extreme care to prevent or reduce such disease transmission. For example, thermometers are thoroughly sterilized or are provided with disposable cases which are thrown away after each use. Great care is taken with the sterilization of surgical instruments. The personal cleanliness of hospital personnel is carefully monitored, and germicidal soaps and the like are regularly employed. Yet, disease transmission within hospitals remains an acute problem, and every person or thing which moves from patient to patient is a potential carrier of disease.